Solid freeform fabrication (SFF) is a process whereby three-dimensional objects, for example, prototype parts, models, working tools, production parts, molds, and other articles are manufactured. Computer aided design (CAD) is commonly used to automate the design process. Using a suitable computer, an operator may design a three-dimensional article and then create that object by the use of a positionable ejection head that selectively emits small mass particles. Many methods have been developed to manufacture SFF objects according to the above principles including stereolithography, selective laser sintering, and powder based three-dimensional printing technologies. The above-mentioned techniques typically include support structures designed to join the SFF object to a system platform and attach any overhangs, large spans, or disjoint areas. The addition of these structures to the CAD model and subsequent manual removal from the SFF article during cleaning is labor intensive and often requires special skills, significantly increasing the cost of fabrication.
One traditional method for forming three-dimensional objects includes a device having two positionable jetting heads with two feeder lines connected to remote sources of material such as melted wax to provide both object and support material. This method and apparatus are able to construct an object from a coordinate representation without regard to the angular dimensions thereof by automatically depositing support material wherever needed to support the build material. In this way, the user need not add support structures to the CAD model; software automatically adds support material wherever needed. One common method uses different waxes having varying melting temperatures for the build and support materials, with the support wax having a lower melting point than the build wax. While this traditional method allows the undesirable support material to be melted away, traditional processes used to clean such SFF articles with phase change support are time consuming, may utilize a hydrocarbon or other organic solvent (which may be noxious), are manual (requiring skilled labor), tedious, and expensive. Traditional cleaning processes may also leave an undesirable waxy support material residue on the surface of the SFF object.